MITOSIS

The cell cycle

The cell cycle: G1 , S, G2,M

1- Growth and normal metabolic roles (first

growth phase)

2- DNA replication (synthesis phase)

3-Growth and preparation for mitosis ( second growth phase)

4-Mitotic phase

G1,S,G2 = interphase

• Overview of Mitosis Cell division is an elegant process that enables organisms to grow and reproduce. Through a sequence of steps, the replicated genetic material in a parent cell is equally distributed to two daughter cells. While there are some subtle differences, mitosis is remarkably similar across organisms. Before a dividing cell enters mitosis, it undergoes a period of growth called interphase. Interphase is the "holding" stage or the stage between two successive cell divisions. In this stage, the cell replicates its genetic material and organelles in preparation for division.

Mitosis is composed of several stages:

• Prophase

• Metaphase

• Anaphase

• Telophase

• Prophase

In prophase, the chromatin condenses into discrete chromosomes. The nuclear envelope breaks down and spindles form at opposite "poles" of the cell.

• Metaphase In metaphase, the chromosomes are aligned at the metaphase plate (a plate that is equally distant from the two spindle poles).

• Anaphase In anaphase, the paired chromosomes (sister chromatids ) move to opposite ends of the cell.

• Telophase In this last stage, the chromosomes are cordoned off in distinct new nuclei in the emerging daughter cells. Cytokinesis is also occurring at this time.

At the end of mitosis, two distinct cells with identical genetic material are produced.

http://en.wikipedia.org/wiki/File:Wilson1900Fig2.jpg